Minamp 1.7: new launcher icon

- Launcher icon is now a supplied asset (masters in art/), with an xhdpi size
  added; make_icons.py only draws the notification icon, redrawn to match:
  an amber play triangle between orange arcs

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

AndroidManifest.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.minamp"
-    android:versionCode="7"
-    android:versionName="1.6"
+    android:versionCode="8"
+    android:versionName="1.7"
     android:installLocation="auto">
 
     <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="10" />